Well screen structure



Oct. 3, 1944. MYERS 2,359,717

WELL SCREEN STRUCTURE Filed Aug. 51, 1945 2 Sheets-Sheet 1 se- 1m Oct. 3, 1944. R. N. MYERS WELL SCREEN STRUCTURE 2 Sheets-Shet 2 Filed Aug. 51, 1945 8 9 5 2 $6??? vz 4 E -s 2 r4 .2 z. 5 L ul F I I .QJ F .mw F M F 2 l F \nwn'for: Richard N. Mgcrs w his AHQFWQM Patented Oct. 3, 1944 2,359,717 WELL SCREEN STRUCTURE Myers, Houston, Shell Development Company,

Tex., asslgnor to San Francisco,

Calii'., a corporation oi Delaware Application August 31, 1943, Serial No. 500,713

Claims.

This invention pertains to screens used in oil and gas wells, and relates more particularly to close a screen while it installed therein, and said screen from the after a period of production.

are undertaken. The capacity of clogged reduced.

or the wire-wrapped operating efllciency and screens is naturally greatly carried in the general manner of ordinary drilling, is known as washing over the screen. When the screen has been washed over its total axial length and is free of retaining obstructions, it can be readily removed from the 'well by means or a device such as a spear tool, Ii" there is no suflicient clearance between the screen and the walls of the borehole, or the length of the screen is too great to permit washing over operations, the screen-is means of an internal cutting too] similar to that used to cut away the packer, and the sections are pulled out of the well separately.

It is therefore an object of this invention to provide a method and apparatus whereby the possibility of inJuring or impairing screens during installation operations is eliminated or minimized, and the operations for retrieving said Y screens from wells in a substantially intact condition are greatly simplified.

It is also an object of this invention to provide'a structure comprising a tubular'string, a screen attached thereto, a housing slidably enclosing said screen, said housing being adapted to be set or anchored in a well and being provided with a tubular cutting head, whereby said housing maybe anchored in a well, the screen forced out of the housing, the well produced through the screen, and the screen finally removed from the well by washing said housing, operated as a rotary cutting head, over the screen to free said screen from obstructing material, in the manner described hereinbelow.

These and other objects of this invention will be understood from the following description, taken with reference to the attached drawings, wherein:

Fig. l is a diagrammatic view, partly in crosssection or the present well structure, and

Figs. 2-5 inculsive are diagrams schematically illustrating a particular sequence of steps forming the process of this inventio Fig. 6 is a detailed view of the latch 56 of Fig 1.

Fig. 1 represents a well 50 provided to a desired level with a casing 30 having a shoe 36. The present well or screen structure is shown .in the well in its retracted position, that is. in'the position in which it is lowered into the well. A tubing string comprising any desired number of tubing sections i, joined together by means of couplings I, is detachalbly connected at its lower end to a shoe 2, preferably by means of lefthand screw-threads 69. The shoe 42 is preferably of the non-return type, and comprises perforations 80, and a valve 13 held against its seat by means of a spring 17, so that fluid may be circulated into the well through the tubing I, but

cannot enter said tubing from the well. Instead of the valve 18, the shoe may be provided with any other suitable non-return valve, such as a ball valve. The shoe may also be provided with a plurality of blades 58.

Attached to the shoe 42 by means such, for example, as right-hand screw-threads 55, and sur-' rounding the lower portion of the tubing string is a tubular screen 55, shown for simplicity as provided with apertures or perforations 53, it being understood that any other type of screen, such as screens comprising a wrapping of wire wound on a tubular member or frame, is suitable for the present invention.

The tubular screen 55 has in its upper portion an outwardly enlarged annular shoulder member 45, provided with a clutch or key member 49, adapted to engage a similar clutch or keyway member 51, as will be explained hereinbelow. The shoulder 45 is likewise provided with an annular gland or packing member 41.

Slidably surrounding the screen 55 is a tubular housing member held in flxed relationship with regard to the string by any suitable looking means, such, for example, as one or more frangible pins made of brass, bronze, copper, steel, or other metal or material. The pin H is shown as connecting the housing 5| with the coupling 1 of the tubing string, although it is obvious that the same result is achieved by connecting the housing 5| directly to the tubing or to any member forming a rigid structure therewith such for example, as the shoulder 45 of screen 55, as long as the tubing screen assembly can slide downwards within the housing 5| when unlocked, as bgthe shearing of pin The housing 5| has in its lower portion an inwardly enlarged annular shoulder member 53. provided with an annular gland or packing member 5|, having a fluid-tight fit about the screen 55, and with a clutch or keyway member 51. Upon a sliding downward motion of the screen 55 with regard to the housing'5l, the screen shoulder 45 comes to rest on the housing shoulder 63, and the key or clutch members 49 and 51 engage each other to prevent any rotational motion of thescreen with regard to the housing 5|.

As shown in greater detail in Fig. 6, the housing 5| is also equipped with one or more latches 55, which are forced by springs 83 against the screen 55 through suitably provided openingsin the housing 5|. Hollow plugs 82 are provided for mounting the springs 83, which force the squarecross section latches against the screen, until the shoulder 85 of the latch and the shoulder 84 of the housing come into contact with each other. A shield 8|) is welded in a streamlined manner to the outside of the housing'5l to protect the latches while running the device into the well. The purpose of latches 55 is to permit the enlarged annular shouldermember 45 to pass the latches in a downward direction but not in an upward direction. Thus, when tubing is released from shoe 42, as will be explained below, the well pressure will not be able to force the screen back into the housing. 7

The housing 5| has also in its upper portion an annular gland or packing member 3, having a fluid tight fit about the tubing string Annular glands 3 and 5| thus provide sealing means for an annular chamber 43 formed between the housing 5| and the tubing string l, which chamber serves to enclose the screen 55. A port closed by a plug 44 is used to fill said chamber with a light grease lubricating oil or other suitable protective and non-corrosive substance, which is forced into chamber 45 until the chamber is full so as to prevent any well fluid from leaking into the chamber 45 during the lowering operation. This port may be installed at the lower end of the chamber to enable the pumping of viscous fluids such as grease into the housing as shown in the drawings, or may be installed at the upper end of the chamber immediately below pin II to facilitate pouring liquid into the housing. An equalizing vent l3 in the housing may be incorporated at the upperend of the housing to permit of equalization of pressure within and without the housing while lowering into the well. This vent would permit equalization of pressure with negligible mixing of the fluids within and without the housing.

Carried outwardly on the housing 5| is a packer member l5, of any desired and suitable type, which is held in place by a slip bowl 2, slidably surrounding the housing and held in place by shear pin l9.

Slidably fitting over the tapered outward face of the slip bowl 2 are slips 23, adapted to engage the casing 30 upon upward motion. The slips are held in place by means of a ring 8 slidably fitting over the housing and connected by means of guide or friction springs 4 with a slidable looking or latch ring 20 having a notch 25 adapted to receive a pin or pins 39, fixedly attached to the housing.

It is obvious that instead of the packer and slips arrangement described above and'shown in Fig. 1, other suitable conventional packer and slips means may be used to achieve the desired purpose as will be shown hereinbelow.

The lower part of the housing 5| has, integrally formed therewith, or attached thereto by means such as welding or screw-threads 59, a rotary shoe or a tubular rotary cutting head provided with a plurality of cutting teeth 40. These teeth are annularly arranged around the central bore of the cutting head, which bore is of a diameter sufllciently large to accommodate the tubular screen 55, but preferably smaller than the outside diameter of shoe 42, which is in turn preferably smaller than the outside diameter of the cutting head 32, for purposes to be described hereinbelow. A key element 54, or an equivalent clutch or friction member, is fixedly attached to the screen 55, while a corresponding keyway or clutch element 54a is provided in the cutting head 53 to prevent rotation of the screen and housing with regard to each other when the screen is in its uppermost position.

The operation of the present device is as follows:

The screen structure or assembly is run into the well at the end of a tubing or drill string When the casing shoe 35, or other desired position above the setting point is reached, washing may be commenced by pumping a'clean fluid down through the tubing I, the fluid pressure forcing the valve 13 down, and the fluid returnin to the surface through the annular space between the screen structure or the tubing and the walls of the well or casing. If any obstruction on the walls of the well impedes the lowering of the string, rotational motion is imparted to the latter, and the teeth 40 and blades 58 cut the obstructions away in the regular drilling manner, the engagement of key 54 with keyway 54a preventing the pin H from shearing due to the housing torque impressed thereon by ation.

The well is washed to the final bottom screen position until the formation can be considered clean or until the well shows a tendencyto flow. The assembly is then raised to such a position that the packer I5 is slightly above the desired final position, for example, to a position slightly above that shown in the drawings. The tubing is then rotated and the friction of the springs l4 against the casing preventing the latch ring from following this rotation, the latch ring 20 is released from engagement with the pin 39. The assembly is then slightly lowered, the rings 20 and 8 and the slips 23 being still. prevented from. following this downward motion of the assembly due to the frictional engagement of the springs M with the casing. This causes the slips 23 to slide over the tapered face of the slip bowl 2 and to engage and grip the casing 30. A downward pressure on the tubing causes the pin H which, by design, has a lower strength than pin l9, to shear, While continuing to wash by pumping, the tubing shoe 42', and screen 55 are then lowered until the whole apertured space of the screen is forced out of the housing 5| and is exposed tothe borehole, and the shoulders 45 and 63 of the screen and housing respectively are in engagement with each other. At this time, the screen is at its fully extended position, is locked. against rotation by clutches 49 and 51, and is prevented from being forced upwards by well or other pressure by latches 56. The wash pump at the surface is then shut down, and additional weight on tubing I, applied to shoe 42, is transmitted, by tension, through screen 55, the contacting upper and lower shoulders of, 63 and 45, and the housing 5|, to pin I9. This will shear pin l9 and thus cause the housing to slide through bowl 2, which is held from downward movement by slips 23, thus expanding the packing I5 against the casing 30, and thus sealing off the flow in the annular space between casing and housing 5|.

Clockwise rotation is then applied to the tubing l, and the lefthand screw joint 69 is thus broken, since the shoe 42 and screen 55 are prevented from rotating by the engagement, through clutch members 495|, with the rigidly anchored After the tubing i has been unscrewed at 69 from the shoe, it may be raised to any desired level, or entirely removed' from the well, production of the well being eifected through the screen, inside of housing 5|, and tubing l or the expanded packer l5. The position of the present device in the well, with the string I removed, is at this moment diagrammatically shown in Fig; 2,. which for clearness omits all. unessential details, such as slips, keys and keyways, etc.

After the well has been produced through the screen throughout a period of time, various matsaid rotary operter, such as scale, wax, sand, etc., usually accu mulates between the screen and the walls of" the borehole, as shown at 80, and jams or freezes the screen to the formation.

Inorder to withdraw the screen from the well,

the following operations are resorted to according to the present method:

A conventional inside cutting tool or knife (not shown) is inserted into the housing 5| at the end of a suitable tubing or drill string, and said housing is cut in a horizontal plane somewhat below thev packer i5, as shown at 84 in Fig, 3,

directly through the casing 30 above into an upper and lower portion. A gripping or spear tool 82 is then inserted into the upper portion and said portion is removed from the well.

A similar spear tool, or a double spear tool 88, having slips 86 adapted to engage the housing 7 5|, and slips 90, adapted to engage the screen a downward pressure is applied to the housing by means of the string for disengaging the key or clutch members 51 and 49, sufiicient clearance being provided between the top of the shoulder and the latch 58 to permit this. A rotary motion and a downward pressure are then applied to the housing by means of the string, whereby the latches are milled out by abrasion with the top surface of shoulder 45, and the housing 5| descends further with rotation around the screen, as shown in Fig. 4, the teeth 40 of the cutting head at the lower end of the housing cutting an annular space around the screen 55. Drilling fluid may be circulated down through the string and nipple 94, returning to the surface through the screen 55 and the an nular space between the string and the casing.

When the housing and the cutting head have cleared the total axial length of the screen 55 down to the shoe 42, the slips 90 engage the screen 55 from the inside, whereupon the screen and the housing may be raised in a single operation. It is obvious, however, that if it is not desired to use a double spear, the same operations may be carried by means of a single spear, or rather of two single spears, for example, the spear 82 of Fig. 3, and another spear similar thereto, but having a diameter adapted to fit for engagement within the screen 55, the first spear being used for washing over the screen and for removing the housing, and the second for separately removing the screen after the housing had been removed.

It is obvious that in order for the housing 5| to. be able to wash over the entire length of the screen while beingheld'byan inside spear, its

length must. be in excess of that of the screen by'a. definite amount, ThusQif'the axial length of that part of the' housin'g'jon which the packer l-iis outwardly mounted, and whichgisla-ter cut away, aslshown inFig'; 3,2is 1-1 the ex l leng-th of that-partof the housing which is: ecessmfor internally accommodating the spear .851 ifsH; and the axial length of the screen is": then-the mustasatis'fy: the} expression H=Hp+Hs+S to permit-theffteethlfl to reach the top of the shoe42 'beforei theslips total length of the housingH 86 come to bear against the as-shown in Fig. 5.

I claim as my invention: I .1. 1. A structure for use inwells, comprising a tubular string adapted. to be lowered into a well, an elongated tubular member surrounding said string adjacent the lower end thereof, a cutting head at the lower end of said member, frangible means locking said tubular member with regard to said string, a shoe detachably conbelow said head, a tubular nected to said string screen aflixed to said shoe and slidably extending thereabove into the annular space between said string and said tubular member, and packer means outwardly mounted on said tubular bit member for anchoring said member within the well.

2. A structure for use in wells, comprising a tubular string adapted to be lowered into a well, an enlongated tubular member surrounding said string adjacent the lower end thereof, a cutting head at the lower end of said member, frangible means locking said tubular member with regard to said tring, a shoe detachably connected to said string below said head, a tubular screen member aflixed to said shoe and slidably extending thereabove into the annular space between said string and said tubular member,

packer means outwardly mounted on said tubular cutting head member for anchoring said member within the well, and stop members carried by saidtubular cutting head and screen members adapted to limit the outward axial motion of said screen with regard to said tubular bit member.

3. A structure for use in wells, comprising a tubular string adapted to be lowered into a well, an elongated tubular cutting head member surrounding said string adiacent the lower end thereof, frangible means locking said tubular cutting head member with regard to said string, a shoe detachably connected to said string below said bit, an apertured tubular screen member anlxed to said shoe and slidably extending'thereabove into the annular space, between said string and said tubular cutting head member, annular packing members sealing said space above and below the apertures of the screen, packer and slips means outwardly mounted on said tubular cutting head member for anchoring said member within a well, stop members respectively carried by said cutting head and screen members adapted to arrest the axial motion of said screen with regard to said cutting head, and key members carried by said cutting head and screen members adapted to prevent a rotational motion of said screen and cutting head with regard to each other.

4. A structure for use in wells, comprising a tubular'string adapted to be lowered into a well, an elongated tubular cutting head member surrounding said string adjacent the lower end thereof, frangible means-locking said tubular bit member with regard to said string, a shoe detachably connected to said string below said bit, an apertured tubular screen member aflixed to said shoe and slidably extending thereabove into the annular space between said string and said tubular cutting head member, annular packing members sealing said space above and below the apertures of the screen, packer and slip means outwardly mounted on said tubular cutting head member for anchoring said member within a well, stop members respectively carried by said cutting head and screen member adapted to limit the outward axial motion of said screen with regard to said tubular cutting head member, key members carried by said cutting head and screen members adapted to prevent a rotational motion of said members with regard to each other, and latch means carried by tubular cutting head member adapted to lock said screen against inward axial motion with regard to said tubular cutting head member.

5. In combination with a well screen attached to the end of a tubular string, a tubular member slidably surrounding said screen, the lower end of said member being provided with annularly arranged rotary teeth, locking means frangibly securing said member with regard to the string, and means comprising a packer and slips for anchoring said member within a well.

' RICHARD N. MYERS. 

